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General Water Microbiology

General Water Microbiology. Robin Cook. FSEA Fall Meeting and Technical Session 10/17/2007. Introduction . Why we do this matters! How we do this matters! This is not just about meeting a regulatory requirement. . Overview . What are we looking for? Why are we looking? . Vocabulary.

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General Water Microbiology

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  1. General Water Microbiology Robin Cook FSEA Fall Meeting and Technical Session 10/17/2007

  2. Introduction Why we do this matters! How we do this matters! This is not just about meeting a regulatory requirement.

  3. Overview • What are we looking for? • Why are we looking?

  4. Vocabulary • Coliform Bacteria = Gram (-),non-spore-forming, facultative anaerobic, rod-shaped bacteria capable of growth in the presence of bile salts and that ferment lactose with production of gas, acid and aldehyde within 48hrs at 35°C. • OR Coliform Bacteria = … possessing the enzyme -galactosidase which cleaves ONPG resulting in a release of a chromogen. • These definitions are operational rather than taxonomic and therefore tied to a method as well.

  5. Vocabulary cont. • This definition includes Enterobacter aerogenes which is NOT typically associated with the intestine. • Depending on which defintion Serratia may or may not be a coliform. Not all species will ferment lactose.

  6. Vocabulary Cont. • Coliforms are members of the enteric bacteria group also know as the Enterbacteriaceae family. • Fecal Coliforms are further defined as thermotolerant coliforms capable of growth with acid and gas formation at 44.5ºC.

  7. Enterobacteriaceae Family • Klebsiella, Enterobacter, Citrobacter, and Escherichia are classified as coliforms. • Escherichiacoli, Citrobacter freundii and thermotolerant Klebsiella pneumoniae are classified as fecal coliforms. • Non-coliforms include Proteus, Serratia (depending), Yersinia, Shigella, and Salmonella. These are excluded only because they do not usually ferment lactose.

  8. Other indicators • Fecal Streptococcus: Gram (+) bacteria which is a normal inhabitant of the GI tract of warm-blooded animals. • Only a few are pathogenic • Persist well, but do not reproduce in the environment. • Many isolates are not associated with humans.

  9. Other indicators cont. • Enterococcus: subgroup of the Fecal Streptococcus • can grow in 6.5% NaCl, at pH 9.6 and at both 10ºC and 45ºC. • Used to check quality of recreational waters

  10. Interesting Trivia • Ratio of FC:FS • FC:FS > 4.0 human contamination • FC:FS < 0.7 animal contamination • Between suggests a mixed source • Only valid in the 1st 24 hours, and technology dependent

  11. Concerns and Disease: • Klebsiella: opportunistic pathogen. Can cause infection in wounds, soft tissue and urinary tract as well as pneumonia in immuno-compromised. • Enterobacter, Citrobacter, and Serratia: mostly hospital-related infections • Serratia is particularly prevalent in maternity wards • E. coli: septiciema, UTI, neonatal meningitis, gastroenteritis and hemorrhagic colitis. • Proteus: UTI and contributes to the formation of kidney stones due to pH change it causes.

  12. Continued • Yersinia: septicemia, enterocolitis, Bubonic Plague. • Shigella: gastrointeritis • Salmonella typhi: Typhoid Fever • Not in the family but grows in the same conditions: Vibrio cholerae which is what causes cholera in untreated water.

  13. Indicator Organisms • Associated with the intestinal tract typically in large numbers • Found in warm-blooded animals as well as humans yet will die once excreted • Death-rate is similar to the pathogenic Salmonella and Shigella • Both coliforms and pathogens react in a similar manner during the water purification process.

  14. Summary • The presence of coliforms indicates a problem • BUT, absence does not necessarily mean that there is not a problem • Need as much information as possible to make a good decision.

  15. References • Brock, Thomas D. et al. Biology of Microorganisms 7th ed. Englewood Cliffs, NJ: Prentice Hall, 1994. • Cullimore, D. Roy. Practical Manual of Groundwater Microbiology. Boca Raton, FL: Lewis, 1993. • Murry, Patrick R., et al. Medical Microbiology 2nd ed. St Loius, MO: Mosby, 1994.

  16. Any questions?

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